def preOrderIter(root):
''' a much easier way, use a stack, push right first and then push left '''
if not root: return
s = Stack()
s.push(root)
while not s.isEmpty():
curr = s.pop()
print curr.value
if curr.right:
s.push(curr.right)
if curr.left:
s.push(curr.left)
bst = BinarySearchTree()
bst.put(6)
bst.put(3)
bst.put(4)
bst.put(7)
bst.put(9)
bst.put(2)
print bst
print '==== post recur ===='
postOrderRecur(bst.root)
print '==== post iter===='
postOrderIter(bst.root)
print '==== post iter 2===='
postOrderIter2(bst.root)
print '==== pre iter===='
preOrderIter(bst.root)
print '==== in recur===='
def bfsIterative(node):
if node is None:
return []
res = []
q = Queue()
q.enqueue(node)
while not q.isEmpty():
tmp = q.dequeue()
res.append(tmp.value)
if tmp.left:
q.enqueue(tmp.left)
if tmp.right:
q.enqueue(tmp.right)
return res
bst = BinarySearchTree()
bst.put(5)
bst.put(2)
bst.put(4)
bst.put(3)
bst.put(1)
bst.put(8)
bst.put(7)
bst.put(9)
print bst
print "dfs iterative: ", dfsIterative(bst.root)
print "dfs recursive: ", dfsRecursive(bst.root)
print "bfs iterative: ", bfsIterative(bst.root)
